Every ZIP code in the United States, with weather, radar, trivia and the numbers behind it. Five digits since 1963!

ZIP stands for Zone Improvement Plan. The codes went live on July 1, 1963.The lowest ZIP code is 00501 — the IRS in Holtsville, New York.The highest ZIP code is 99950, in Ketchikan, Alaska.Type 07734 into a calculator and turn it upside down: hELLO. It is Keansburg, New Jersey.12345 belongs to one company: General Electric in Schenectady, New York.The first digit is a region: 0 is New England and New Jersey, 9 is the West Coast, Alaska and Hawaii.Mr. ZIP, the cartoon mailman, was the mascot that sold the idea to America.ZIP+4 arrived in 1983 and can narrow a ZIP down to one side of one block.A ZIP code is a mail route, not a place: plenty of them cross county and even state lines.Play ZIP Hunt: guess the secret ZIP code of the day in six tries.
zipcodes.pro — AREA-CODE/621

621 area code

Area code 621 is in Texas. It covers the same places as 346: Houston, Cypress, League City and 33 other places, 284 ZIP codes in Harris, Fort Bend, Montgomery and 6 other counties. Local time there is , Central Time. In service since 2025 as an overlay: it covers the same area as 281, 346, 713 and 832, so a number from there can have any of them.

State
Texas
Time zone
Central
Overlays
281, 346, 713, 832
In service since
2025
Rate centres
0
Prefixes assigned
0 (0 numbers)

Who calls from a 621 number

An area code says where a number was issued, not where the caller is: people keep their numbers when they move, and caller ID can be set to show any number, which the FCC calls spoofing. If a call you did not expect asks for money or personal details, the FCC advises hanging up and calling the company back on a number you look up yourself. Unwanted calls can be reported to the FTC at ReportFraud.ftc.gov.

Places in area code 621

621 has no prefixes in use yet. It overlays 346, so it covers the same 36 places, largest first.

Places in area code 621
PlaceZIP codesPopulation
Houston, TX 178 2,328,253
Cypress, TX 3 212,884
League City, TX 2 116,215
Sugar Land, TX 5 110,016
Baytown, TX 4 85,205
Missouri City, TX 2 76,558
Spring, TX 12 68,580
Porter, TX 1 46,418
Channelview, TX 1 43,605
Friendswood, TX 2 41,030
La Porte, TX 2 36,730
Deer Park, TX 1 33,967
Alvin, TX 2 28,333
Katy, TX 6 25,184
Dickinson, TX 1 21,753
Stafford, TX 2 17,401
Humble, TX 4 16,521
Manvel, TX 1 14,758
Huffman, TX 1 14,342
Seabrook, TX 1 13,768
Tomball, TX 2 13,655
Mont Belvieu, TX 1 9,020
Cleveland, TX 2 8,984
Highlands, TX 1 6,335
Brookshire, TX 1 5,495
Crosby, TX 1 4,617
Pinehurst, TX — 4,266
Beach City, TX — 3,309
Sheldon, TX — 2,208
Kemah, TX 1 2,168
Splendora, TX 1 2,131
Arcola, TX — 1,911
Rosharon, TX 1 1,737
Porter Heights, TX — 987
Liverpool, TX 1 477
Barker, TX 1 —

ZIP codes in area code 621

284 ZIP codes in 54 towns, by the town each is mailed to, largest first. They are 346's, which 621 overlays. Each links to its own page.

Houston
77001, 77002, 77003, 77004, 77005, 77006, 77007, 77008, 77009, 77010, 77011, 77012, 77013, 77014, 77015, 77016, 77017, 77018, 77019, 77020, 77021, 77022, 77023, 77024, 77025, 77026, 77027, 77028, 77029, 77030, 77031, 77032, 77033, 77034, 77035, 77036, 77037, 77038, 77039, 77040, 77041, 77042, 77043, 77044, 77045, 77046, 77047, 77048, 77049, 77050, 77051, 77052, 77053, 77054, 77055, 77056, 77057, 77058, 77059, 77060, 77061, 77062, 77063, 77064, 77065, 77066, 77067, 77068, 77069, 77070, 77071, 77072, 77073, 77074, 77075, 77076, 77077, 77078, 77079, 77080, 77081, 77082, 77083, 77084, 77085, 77086, 77087, 77088, 77089, 77090, 77091, 77092, 77093, 77094, 77095, 77096, 77098, 77099, 77201, 77202, 77203, 77204, 77205, 77206, 77207, 77208, 77209, 77210, 77212, 77213, 77215, 77216, 77217, 77218, 77219, 77220, 77221, 77222, 77223, 77224, 77225, 77226, 77227, 77228, 77229, 77230, 77231, 77233, 77234, 77235, 77236, 77237, 77238, 77240, 77241, 77242, 77243, 77244, 77245, 77248, 77249, 77251, 77252, 77253, 77254, 77255, 77256, 77257, 77258, 77259, 77261, 77262, 77263, 77265, 77266, 77267, 77268, 77269, 77270, 77271, 77272, 77273, 77274, 77275, 77277, 77279, 77280, 77282, 77284, 77287, 77288, 77289, 77290, 77291, 77292, 77293, 77297, 77299

Counties

The counties of its ZIP codes, most residents first, with how many of its ZIP codes each has.

Which code covers where you are now? What area code am I in? answers from your location.

Questions about area code 621

Where is area code 621?

Area code 621 is in Texas. It covers the same places as 346: Houston, Cypress, League City and 33 other places, 284 ZIP codes in Harris, Fort Bend, Montgomery and 6 other counties.

What ZIP codes are in area code 621?

284 ZIP codes, by the town each is mailed to: Houston (178, 77001 to 77299), Cypress (3, 77410 to 77433), League City (2, 77573 to 77574), Sugar Land (5, 77478 to 77498) and 50 more towns. The full list is on this page.

What time zone is area code 621 in?

Central time.

What area codes overlay 621?

281, 346, 713 and 832. They cover the same area as 621, so a new number there can be given any of them.

Does a 621 number mean the caller is in Texas?

Not necessarily. An area code says where the number was first issued. People keep their numbers when they move or switch carriers, and calling software can show any number, so a 621 call can come from anywhere.

Other area codes in Texas

All 29 Texas area codes, by area, with the cities each covers

Source: NANPA NPA database, central office code and thousands-block assignments, 2026-10-10. Places are matched to NANPA's rate centres by name; see sources.

Cite this page

zipcodes.pro. “Area code 621.” Data release 2026-10-12. Retrieved 2026-10-20. https://zipcodes.pro/area-code/621

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